Conventional overhead garage doors have panels or sections which for many years were predominantly of wood construction. Recently, the trend has been to doors with panels comprising a synthetic foam core encased in a weather-resistant outer skin of metal. Such doors were normally somewhat more expensive than wood doors but tend to be no more noisy in operation than wood doors. Moreover, the synthetic foam core is desirable to provide increased thermal insulation.
Certain prior doors of this type, as shown for example in U.S. Pat. No. 4,339,487, were provided with longitudinal ribs in the metallic skin in order to minimize waviness of distortion which tends to occur in the metal, especially as a result of stretching the metal when roll-forming the edges or shiplaps. However, the longitudinal ribs added weight and expense and imparted an unattractive appearance, making such constructions unsuitable for residential overhead garage doors.
The smaller lighter weight residential garage doors have been made of composite steel skin and synthetic foam core without the longitudinal stiffening ribs, thereby producing a door of excellent thermal insulation properties and relatively quiet operation. However, such doors have been more expensive and heavier and less attractive than wood doors.